High throughput pH optimization of protein crystallization

Abstract

Most high throughput structural proteomics centers use the sitting-drop method to obtain diffracting crystals for three-dimensional (3D) structure determination of biological macromolecules by x-ray crystallography. Although several robotic systems are available for dispensing the initial sitting-drop screening conditions, generally they are not used for optimization of crystallization conditions. This chapter describes a protocol for such automated systems, which permits easy construction of pH optimization grids using any desired fixed buffer set with varying ionic strengths directly dispensed into the crystallization plate.